阅读说明：本技术 一种新型高纯5n级铼粒制备工艺 (Novel preparation process of high-purity 5N-grade rhenium particles ) 是由 俞鹰 方支灵 蔡晨龙 钱俊杰 潘荣选 戴超 申其新 于 2021-09-09 设计创作，主要内容包括：本发明公开一种新型5N级高纯铼粒制备工艺,包括粗铼酸铵预处理、高温氢气还原、铼粉一次研磨筛分、铼粉真空蒸馏、铼粉二次研磨筛分、压制成型及真空活化烧结。使用本发明提供的工艺能够制备出纯度大于5N的高纯铼粒产品且73种杂质元素总含量低于10ppm。(The invention discloses a novel 5N-grade high-purity rhenium particle preparation process which comprises the steps of coarse ammonium rhenate pretreatment, high-temperature hydrogen reduction, primary grinding and screening of rhenium powder, vacuum distillation of the rhenium powder, secondary grinding and screening of the rhenium powder, press forming and vacuum activation sintering. The process provided by the invention can be used for preparing a high-purity rhenium particle product with the purity of more than 5N and the total content of 73 impurity elements of less than 10 ppm.)

1. A novel preparation process of high-purity 5N-grade rhenium particles comprises the following steps:

s1, pretreating coarse ammonium rhenate: ball-milling, sieving and grading 99.9-99.99% of crude ammonium rhenate to prepare ammonium rhenate powder with the particle size of 200-400 meshes;

s2, high-temperature hydrogen reduction: putting the obtained ammonium rhenate powder into a molybdenum boat, and then conveying the molybdenum boat filled with crude ammonium rhenate into a tubular hydrogen reduction furnace for high-temperature reduction;

s3, primary grinding and screening: grinding, sieving and grading the obtained reduced rhenium powder to prepare 200-400-mesh rhenium powder;

s4, and vacuum distillation of rhenium powder: loading the 200-mesh 400-mesh rhenium powder into a molybdenum boat, then placing the boat into a tubular vacuum furnace, and controlling a certain temperature and a certain vacuum degree to carry out vacuum distillation;

s5, secondary grinding and screening: grinding, sieving and grading the reduced rhenium powder obtained by vacuum distillation to prepare 800-mesh rhenium powder with the particle size of 600-;

s6, press forming: pressing and molding the rhenium powder obtained by secondary grinding through a particle pressing machine to obtain cylindrical rhenium particles with the specification;

s7, vacuum activation sintering: and putting the pressed and formed rhenium particles into a vacuum sintering furnace, and sintering the rhenium particles into porous rhenium particles under certain temperature conditions.

2. The novel preparation process of high-purity 5N-grade rhenium particles according to claim 1, wherein in S1, the parts of the ball mill, which are in contact with the ammonium rhenate, are made of agate materials, the particle size of agate balls is 0.5-3.0mm, the ball milling time is 1-3h, and a PPH (polypropylene-random-H) material screen is adopted for screening.

3. The novel process for preparing high-purity 5N-grade rhenium particles according to claim 1, wherein in S2, an ammonium rhenate powder layer is laid to a thickness of 1-10 mm.

4. The novel preparation process of high-purity 5N-grade rhenium particles as claimed in claim 1, wherein in S2, the ammonium rhenate hydrogen reduction temperature is controlled to be at three different temperature regions of 550-650 ℃, 700-800 ℃ and 900-1000 ℃, and each temperature region is set with different reaction time according to requirements.

5. The process for preparing 5N-grade rhenium particles as claimed in claim 1, wherein in S2, argon or nitrogen is introduced to exhaust air, then hydrogen is introduced to reduce, and the hydrogen flow rate is controlled to be 0.5-3m³H is used as the reference value. Wherein the concentration of argon or nitrogen is more than 99.99 percent, and the concentration of hydrogen is 99.999 percent.

6. The process of claim 1, wherein in step S4, the material layer in the molybdenum boat is laid to a thickness of 1.0-5.0 mm; controlling the vacuum degree of the vacuum distillation furnace to be 1.0-10 pa; the temperature of the vacuum distillation furnace is set to 900-1600 ℃, and the vacuum distillation time is 2-6 h; before vacuumizing, firstly introducing argon or nitrogen to exhaust air, and then vacuumizing, wherein the concentration of argon or nitrogen is more than 99.99%.

7. The process of claim 1, wherein in step S5, the grinding device is agate and the screening device is 316L stainless steel screen.

8. The process of claim 1, wherein in step S6, the pressure of the pelletizer is 1.0-20.0Mpa, so that the rhenium particles have a certain porosity; the specification size of the rhenium particles is controlled to be 10-20mm in diameter and 10-25mm in height.

9. The process according to any one of claims 1 to 8, wherein in S7, the vacuum activation sintering temperature is 1000-1600 ℃, and the temperature rise rate is set for the vacuum activation sintering; the vacuum degree of vacuum activation sintering is 1.0-50 Pa; the vacuum activation sintering time is 6-24 h.

Technical Field

The invention relates to the field of rhenium particle preparation processes, and particularly relates to a preparation process of high-purity 5N-grade rhenium particles.

Background

Rhenium is a silver-white band metallic luster metal, rhenium powder is black at low temperature, and is heated to 1000 ℃ to become gray. Rhenium has a melting point second only to tungsten. Rhenium is more stable to oxidizing agents than tungsten, and is similar to platinum. At present, domestic processes for preparing high-purity rhenium powder comprise a hydrogen reduction method, a wet one-step reduction process and the like, and the main process is mainly hydrogen reduction and is widely applied to industry. The wet reduction process reduces high-purity rhenium powder from the ammonium rhenate solution in one step, and is usually reported, but is not applied industrially. The hydrogen reduction process for preparing high-purity rhenium powder has the precondition that the purity of the raw material ammonium rhenate is more than 99.99%, the impurity content of the raw material ammonium rhenate meets the established requirement, and a high-purity rhenium product meeting the requirement can be prepared, so that the preparation process flow process of the high-purity rhenium is high, and the cost is high.

In recent years, research is also carried out on the preparation of rhenium particles, for example, the publication number is CN111872409A, a production process of high-purity aviation-grade rhenium particles is disclosed, which comprises six procedures of ammonium perrhenate pretreatment, high-temperature reduction, grinding classification, press forming, high-temperature sintering and surface treatment, wherein in the production process of the rhenium particles, two times of high-temperature reduction and compression are carried out for one time of reduction, and two times of high-temperature sintering and compression are carried out for one time of sintering, so that the process flow is shortened, the process doping links are reduced, the processing period is shortened, the processing cost is correspondingly reduced, and the size and the density of the rhenium particles can be adjusted according to requirements. However, the total amount of impurities in the scheme is still more, and the requirements of 5N grade and higher cannot be met.

Disclosure of Invention

The invention aims to solve the problems of low purity, more impurities and more pretreatment processes of high-purity rhenium in the prior art, and provides a preparation process of high-purity 5N-grade rhenium particles.

The technical scheme adopted by the invention is as follows: a novel preparation process of high-purity 5N-grade rhenium particles comprises the following steps: s1, pretreating coarse ammonium rhenate: ball-milling, sieving and grading 99.9-99.99% of crude ammonium rhenate to prepare ammonium rhenate powder with the particle size of 200-400 meshes; s2, high-temperature hydrogen reduction: putting the obtained ammonium rhenate powder into a molybdenum boat, and then conveying the molybdenum boat filled with crude ammonium rhenate into a tubular hydrogen reduction furnace for high-temperature reduction; s3, primary grinding and screening: grinding, sieving and grading the obtained reduced rhenium powder to prepare 200-400-mesh rhenium powder; s4, and vacuum distillation of rhenium powder: loading the 200-mesh 400-mesh rhenium powder into a molybdenum boat, then placing the boat into a tubular vacuum furnace, and controlling a certain temperature and a certain vacuum degree to carry out vacuum distillation; s5, secondary grinding and screening: grinding, sieving and grading the reduced rhenium powder obtained by vacuum distillation to prepare 800-mesh rhenium powder with the particle size of 600-; s6, press forming: pressing and molding the rhenium powder obtained by secondary grinding through a particle pressing machine to obtain cylindrical rhenium particles with the specification; s7, vacuum activation sintering: putting the pressed and formed rhenium grains into a vacuum sintering furnace, and sintering the rhenium grains into porous rhenium grains under the conditions of certain temperature, time and vacuum degree.

As a further improvement of the invention, in S1, the parts of the ball mill in contact with the ammonium rhenate are made of agate materials, the particle size of agate balls is 0.5-3.0mm, the ball milling time is 1-3h, and a PPH material screen is adopted for screening.

As a further improvement of the invention, in S2, the ammonium rhenate powder layer is laid to a thickness of 1-10 mm.

As a further improvement of the invention, in S2, the ammonium rhenate hydrogen reduction temperature is controlled to be three different temperature regions of 550-650 ℃, 700-800 ℃, 900-1000 ℃ and the like, and each temperature region is set with different reaction time according to requirements.

As a further improvement of the invention, in S2, argon or nitrogen is firstly introduced to exhaust air, then hydrogen is introduced to carry out reduction, and the hydrogen flow rate is controlled to be 0.5-3m³H is used as the reference value. Wherein the concentration of argon or nitrogen is more than 99.99 percent, and the concentration of hydrogen is 99.999 percent.

As a further improvement of the invention, in S4, the material layer in the molybdenum boat is paved to be 1.0-5.0mm in thickness; controlling the vacuum degree of the vacuum distillation furnace to be 1.0-10 pa; the temperature of the vacuum distillation furnace is set to 900-1600 ℃, and the vacuum distillation time is 2-6 h; before vacuumizing, firstly introducing argon or nitrogen to exhaust air, and then vacuumizing, wherein the concentration of argon or nitrogen is more than 99.99%.

As a further improvement of the invention, in S5, the grinding equipment is made of agate, and a 316L stainless steel screen is adopted for screening.

As a further improvement of the invention, in S6, the pressure of the granulator is 1.0-20.0Mpa, so that the rhenium particles have certain porosity; the specification size of the rhenium particles is controlled to be 10-20mm in diameter and 10-25mm in height.

As a further improvement of the invention, in S7, the vacuum activated sintering temperature is 1000-1600 ℃, and the temperature rise rate is set for the vacuum activated sintering; the vacuum degree of vacuum activation sintering is 1.0-50 Pa; the vacuum activation sintering time is 6-24 h.

The invention has the following beneficial effects: the rhenium particle preparation process firstly has relatively low requirement on the purity of the raw material ammonium rhenate; secondly, adopting one-time high-temperature hydrogen reduction to obtain a rhenium powder product; most importantly, the rhenium powder is subjected to vacuum distillation treatment, and most of low-melting-point metals, such as K, Na, Pb, Zn, Cd, Bi, C, N, P and the like, are effectively removed, so that the product purity is improved, the pretreatment process flow of the raw material ammonium rhenate is reduced, the recovery rate of the metal rhenium is improved, and the way of introducing impurity metals into the product is reduced. In order to further improve the purity of the final product, reduce the sintering energy consumption and reduce the influence of equipment materials on the final product caused by high temperature, the invention adopts low-temperature vacuum activation sintering, the ultrafine rhenium powder with the granularity of 600-plus-800 meshes is prepared by grinding and screening the vacuum distillation rhenium powder, and then the porous rhenium particles are formed in the sintering process by low-pressure pressing and forming. Meanwhile, vacuum sintering is utilized, so that the sintering temperature and energy consumption are reduced, and the product purity is improved. The process provided by the invention can be used for preparing a high-purity rhenium particle product with the purity of more than 5N and the total content of 73 impurity elements of less than 10 ppm.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The present invention will be further described with reference to the following examples.

Example 1: 300g of coarse ammonium rhenate with the effective component of 99.9 percent is taken to be ball-milled, sieved and classified, and ammonium rhenate powder with the particle size of 200 meshes is prepared. Putting the obtained ammonium rhenate powder into a molybdenum boat, laying an ammonium rhenate material layer in the boat to a thickness of 5mm, then sending the molybdenum boat filled with crude ammonium rhenate into a tubular hydrogen reduction furnace for high-temperature reduction, controlling the reduction temperature to be three different temperature regions of 550-650 ℃, 700-800 ℃ and 900-1000 ℃, and setting different reaction time for each temperature region according to requirements. In the reduction process, firstly introducing argon or nitrogen to exhaust air, then introducing hydrogen to carry out reduction, and controlling the hydrogen flow to be 0.5m³And h, obtaining reduced rhenium powder. And grinding, sieving and grading the obtained reduced rhenium powder, and grinding and sieving to prepare the rhenium powder with the particle size of 200 meshes. And (3) loading the 200-mesh rhenium powder into a molybdenum boat, controlling the thickness of a material layer in the boat to be 2mm, controlling the vacuum degree of a vacuum distillation furnace to be 1.0pa, setting the temperature to be 1000 ℃, and controlling the vacuum distillation time to be 3h, wherein the vacuum distillation furnace adopts vacuum pumping, argon or nitrogen is introduced, and the air in the furnace is exhausted in the vacuum pumping mode. And grinding, sieving and grading the reduced rhenium powder obtained by vacuum distillation to prepare the rhenium powder with the particle size of 600 meshes. And pressing and molding the rhenium powder obtained by secondary grinding through a granulator to obtain the cylindrical rhenium granules with the specification, wherein the pressure of the granulator is controlled to be 8Mpa, and the specification size of the rhenium granules is 10mm in diameter and 15mm in height. Putting the pressed and formed rhenium particles into a vacuum sintering furnace, setting the vacuum activation sintering temperature to be 1400 ℃, setting the heating rate for the vacuum activation sintering, setting the vacuum activation sintering time to be 12h, and setting the vacuum degree of the vacuum activation sintering to be 1.0 Pa. 190g of 99.9992% high purity rhenium particles were obtained by the above process.

Example 1 results of inspection of rhenium pellet products

Example 2: and (3) taking 500g of crude ammonium rhenate with 99.95% of active ingredients to perform ball milling, sieving and grading to prepare ammonium rhenate powder with the particle size of 200 meshes. Putting the obtained ammonium rhenate powder into a molybdenum boat in which the ammonium rhenate material is arrangedThe layer laying thickness is 8mm, then the molybdenum boat filled with crude ammonium rhenate is sent into a tubular hydrogen reduction furnace for high-temperature reduction, the reduction temperature is controlled to be three different temperature regions of 550-650 ℃, 700-800 ℃ and 900-1000 ℃, and different reaction time is set for each temperature region according to requirements. In the reduction process, firstly introducing argon or nitrogen to exhaust air, then introducing hydrogen to carry out reduction, and controlling the hydrogen flow to be 1.0m³And h, obtaining reduced rhenium powder. And grinding, sieving and grading the obtained reduced rhenium powder, and grinding and sieving to prepare the rhenium powder with the particle size of 200 meshes. And (3) loading the 200-mesh rhenium powder into a molybdenum boat, controlling the thickness of a material layer in the boat to be 3mm, controlling the vacuum degree of a vacuum distillation furnace to be 5.0pa, setting the temperature to be 1200 ℃, and controlling the vacuum distillation time to be 4h, wherein the vacuum distillation furnace adopts vacuum pumping, argon or nitrogen is introduced, and the air in the furnace is exhausted in the vacuum pumping mode. And grinding, sieving and grading the reduced rhenium powder obtained by vacuum distillation to prepare the rhenium powder with the particle size of 600 meshes. And pressing and molding the rhenium powder obtained by secondary grinding through a granulator to obtain the cylindrical rhenium granules with the specification, wherein the pressure of the granulator is controlled to be 10Mpa, and the specification size of the rhenium granules is 15mm in diameter and 20mm in height. Putting the pressed and formed rhenium particles into a vacuum sintering furnace, setting the vacuum activation sintering temperature to be 1600 ℃, setting the heating rate for the vacuum activation sintering, setting the vacuum activation sintering time to be 8h, and setting the vacuum degree of the vacuum activation sintering to be 1.0 Pa. 400g of 99.995% high purity rhenium particles were obtained by the above process.

Example 2 inspection results for rhenium pellet products

Example 3: 200g of coarse ammonium rhenate with the effective component of 99.9% is taken to be ball-milled, sieved and classified, and ammonium rhenate powder with the particle size of 200 meshes is prepared. Putting the obtained ammonium rhenate powder into a molybdenum boat, laying an ammonium rhenate material layer in the boat to the thickness of 3mm, then sending the molybdenum boat filled with crude ammonium rhenate into a tubular hydrogen reduction furnace for high-temperature reduction, controlling the reduction temperature to be three different temperature regions of 550-650 ℃, 700-800 ℃, 900-1000 ℃ and the like, and setting different anti-ion temperature regions for each temperature region according to requirementsTime should be taken. In the reduction process, firstly introducing argon or nitrogen to exhaust air, then introducing hydrogen to carry out reduction, and controlling the hydrogen flow to be 1.5m³And h, obtaining reduced rhenium powder. And grinding, sieving and grading the obtained reduced rhenium powder, and grinding and sieving to prepare the rhenium powder with the particle size of 200 meshes. And (3) loading the 200-mesh rhenium powder into a molybdenum boat, controlling the thickness of a material layer in the boat to be 2mm, controlling the vacuum degree of a vacuum distillation furnace to be 10.0pa, setting the temperature to be 1200 ℃, and carrying out vacuum distillation for 5 hours, wherein the vacuum distillation furnace adopts vacuum pumping, argon or nitrogen is introduced, and the air in the furnace is exhausted in the vacuum pumping mode. And grinding, sieving and grading the reduced rhenium powder obtained by vacuum distillation to prepare the rhenium powder with the particle size of 800 meshes. And pressing and molding the rhenium powder obtained by secondary grinding through a granulator to obtain the cylindrical rhenium granules with the specification, wherein the pressure of the granulator is controlled to be 15Mpa, and the specification size of the rhenium granules is 15mm in diameter and 20mm in height. Putting the pressed and formed rhenium particles into a vacuum sintering furnace, setting the vacuum activation sintering temperature to be 1600 ℃, setting the heating rate for the vacuum activation sintering, setting the vacuum activation sintering time to be 16h, and setting the vacuum degree of the vacuum activation sintering to be 1.0 Pa. 120g of 99.995% high purity rhenium particles were obtained by the above process.

Example 3 inspection results for rhenium pellet products

The rhenium particle preparation process firstly has relatively low requirement on the purity of the raw material ammonium rhenate; secondly, adopting one-time high-temperature hydrogen reduction to obtain a rhenium powder product; most importantly, the rhenium powder is subjected to vacuum distillation treatment, and most of low-melting-point metals, such as K, Na, Pb, Zn, Cd, Bi, C, N, P and the like, are effectively removed, so that the product purity is improved, the pretreatment process flow of the raw material ammonium rhenate is reduced, the recovery rate of the metal rhenium is improved, and the way of introducing impurity metals into the product is reduced. In order to further improve the purity of the final product, reduce the sintering energy consumption and reduce the influence of equipment materials on the final product caused by high temperature, the invention adopts low-temperature vacuum activation sintering, the ultrafine rhenium powder with the granularity of 600-plus-800 meshes is prepared by grinding and screening the vacuum distillation rhenium powder, and then the porous rhenium particles are formed in the sintering process by low-pressure pressing and forming. Meanwhile, vacuum sintering is utilized, so that the sintering temperature and energy consumption are reduced, and the product purity is improved. The process provided by the invention can be used for preparing a high-purity rhenium particle product with the purity of more than 5N and the total content of 73 impurity elements of less than 10 ppm.

It should be understood by those skilled in the art that the protection scheme of the present invention is not limited to the above-mentioned embodiments, and various permutations, combinations and modifications can be made on the above-mentioned embodiments without departing from the spirit of the present invention, and the modifications are within the scope of the present invention.